:root {
    --brand-blue: #0066FF;
    --brand-blue-dark: #0052CC;
    --brand-blue-soft: rgba(0, 102, 255, 0.08);
    --bg-base: #F5F7FA;
    --bg-header: #FFFFFF;
    --surface: #FFFFFF;
    --surface-border: #E5E8EF;
    --text-primary: #1D2129;
    --text-secondary: #4E5969;
    --text-tertiary: #86909C;
    --accent-gold: #FF7D00;
    --accent-green: #00B42A;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.06);
    --radius-lg: 12px;
    --radius-md: 8px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
}

html {
    -webkit-text-size-adjust: 100%;
}

body {
    background-color: var(--bg-base);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    min-width: 0;
}

a {
    text-decoration: none;
    color: inherit;
    transition: color 0.2s ease;
}

ul {
    list-style: none;
}

input, button {
    background: none;
    border: none;
    outline: none;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* --- 顶部导航 --- */
.site-header {
    background: var(--bg-header);
    border-bottom: 1px solid var(--surface-border);
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--shadow-sm);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
}

.brand-block {
    display: flex;
    align-items: center;
    gap: 10px;
}

.brand-logo {
    width: 36px;
    height: 36px;
    object-fit: cover;
    border-radius: 8px;
}

.brand-block h1 {
    font-size: 18px;
    font-weight: 600;
    color: var(--text-primary);
    letter-spacing: 0.3px;
}

.nav-menu {
    display: flex;
    gap: 36px;
}

.nav-link a {
    font-size: 14px;
    color: var(--text-secondary);
    font-weight: 500;
    position: relative;
    padding: 4px 0;
}

.nav-link a:hover,
.nav-link.is-current a {
    color: var(--brand-blue);
}

.nav-link.is-current a::after {
    content: '';
    position: absolute;
    left: 0;
    right: 0;
    bottom: -2px;
    height: 2px;
    background: var(--brand-blue);
    border-radius: 1px;
}

.menu-trigger {
    display: none;
}

.menu-backdrop {
    display: none;
}

.nav-panel-head {
    display: none;
}

body.menu-open {
    overflow: hidden;
}

/* --- 主体内容 --- */
.page-main {
    padding: 32px 0 64px;
}

.block-heading {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 24px;
    color: var(--text-primary);
    padding-left: 12px;
    border-left: 3px solid var(--brand-blue);
}

.order-panel {
    background: var(--surface);
    border: 1px solid var(--surface-border);
    border-radius: var(--radius-lg);
    padding: 36px 40px;
    box-shadow: var(--shadow-md);
    margin-bottom: 32px;
}

.field-row {
    margin-bottom: 28px;
}

.field-label {
    display: block;
    font-size: 14px;
    color: var(--text-secondary);
    margin-bottom: 10px;
    font-weight: 500;
}

.field-input-wrap {
    max-width: 460px;
    width: 100%;
}

.field-text {
    width: 100%;
    height: 48px;
    background: var(--bg-base);
    border: 1px solid var(--surface-border);
    border-radius: var(--radius-md);
    padding: 0 14px;
    color: var(--text-primary);
    font-size: 15px;
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.field-text:focus {
    border-color: var(--brand-blue);
    box-shadow: 0 0 0 3px var(--brand-blue-soft);
    background: var(--surface);
}

/* 面值选择 */
.price-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 14px;
}

.price-card {
    position: relative;
    background: var(--bg-base);
    border: 1.5px solid var(--surface-border);
    border-radius: var(--radius-md);
    padding: 18px 16px;
    cursor: pointer;
    text-align: center;
    transition: border-color 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
}

.price-card:hover {
    border-color: #C9CDD4;
    box-shadow: var(--shadow-sm);
}

.price-card.is-active {
    border-color: var(--brand-blue);
    background: var(--brand-blue-soft);
    box-shadow: 0 0 0 1px var(--brand-blue);
}

.price-card input[type="radio"] {
    position: absolute;
    opacity: 0;
    width: 0;
    height: 0;
}

.price-coins {
    font-size: 22px;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 4px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 4px;
}

.price-coins::after {
    content: '比心币';
    font-size: 12px;
    font-weight: 400;
    color: var(--text-tertiary);
}

.price-rmb {
    font-size: 13px;
    color: var(--text-tertiary);
    margin-top: 2px;
}

.gift-badge {
    position: absolute;
    top: 0;
    right: 0;
    padding: 3px 8px;
    font-size: 11px;
    font-weight: 600;
    color: #FFF;
    background: var(--accent-gold);
    border-radius: 0 var(--radius-md) 0 var(--radius-md);
    line-height: 1.4;
}

.price-card.has-gift {
    padding-top: 20px;
}

.price-extra {
    font-size: 12px;
    color: var(--accent-gold);
    margin-bottom: 4px;
    font-weight: 500;
}

.price-card.is-active .price-extra {
    color: #D25F00;
}

.gift-note {
    color: var(--accent-gold);
    font-size: 13px;
    margin-left: 4px;
}

.summary-line {
    margin-bottom: 4px;
    font-size: 14px;
    color: var(--text-secondary);
}

.summary-detail {
    font-size: 14px;
    color: var(--text-tertiary);
}

.summary-detail strong {
    color: var(--text-primary);
    font-size: 16px;
    font-weight: 700;
}

/* 支付渠道 */
.channel-list {
    display: flex;
    gap: 14px;
    flex-wrap: wrap;
}

.channel-item {
    position: relative;
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 12px 24px;
    background: var(--bg-base);
    border: 1.5px solid var(--surface-border);
    border-radius: var(--radius-md);
    cursor: pointer;
    font-size: 14px;
    font-weight: 500;
    color: var(--text-secondary);
    transition: all 0.2s ease;
}

.channel-item input[type="radio"] {
    position: absolute;
    opacity: 0;
    width: 0;
    height: 0;
}

.channel-icon {
    width: 22px;
    height: 22px;
    object-fit: contain;
    flex-shrink: 0;
}

.channel-item.is-active[data-channel="alipay"] {
    border-color: #1677FF;
    background: rgba(22, 119, 255, 0.06);
    color: var(--text-primary);
}

.channel-item.is-active[data-channel="wechat"] {
    border-color: var(--accent-green);
    background: rgba(0, 180, 42, 0.06);
    color: var(--text-primary);
}

/* 提交区域 */
.order-footer {
    margin-top: 36px;
    border-top: 1px solid var(--surface-border);
    padding-top: 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 16px;
}

.summary-amount {
    font-size: 26px;
    font-weight: 700;
    color: var(--brand-blue);
    margin-left: 8px;
}

.btn-primary {
    height: 48px;
    padding: 0 40px;
    background: var(--brand-blue);
    color: #FFF;
    font-size: 15px;
    font-weight: 600;
    border-radius: var(--radius-md);
    cursor: pointer;
    box-shadow: 0 2px 8px rgba(0, 102, 255, 0.25);
    transition: background 0.2s ease, box-shadow 0.2s ease;
}

.btn-primary:hover {
    background: var(--brand-blue-dark);
    box-shadow: 0 4px 12px rgba(0, 102, 255, 0.35);
}

/* --- 说明与帮助 --- */
.content-columns {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
    margin-bottom: 48px;
}

.content-card {
    background: var(--surface);
    border: 1px solid var(--surface-border);
    border-radius: var(--radius-lg);
    padding: 28px 32px;
    box-shadow: var(--shadow-sm);
}

.guide-list li {
    position: relative;
    padding-left: 14px;
    margin-bottom: 12px;
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.7;
}

.guide-list li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 10px;
    width: 5px;
    height: 5px;
    background: var(--brand-blue);
    border-radius: 50%;
}

.guide-list li strong {
    color: var(--text-primary);
    font-weight: 600;
}

.qa-block {
    margin-bottom: 16px;
    padding-bottom: 16px;
    border-bottom: 1px solid var(--surface-border);
}

.qa-block:last-child {
    border: none;
    padding-bottom: 0;
    margin-bottom: 0;
}

.qa-title {
    font-size: 14px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 6px;
    display: flex;
    gap: 8px;
    align-items: baseline;
}

.qa-title span {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 22px;
    height: 22px;
    background: var(--brand-blue-soft);
    color: var(--brand-blue);
    border-radius: 4px;
    font-size: 12px;
    font-weight: 700;
    flex-shrink: 0;
}

.qa-body {
    font-size: 13px;
    color: var(--text-secondary);
    padding-left: 30px;
    line-height: 1.7;
}

/* --- 页脚 --- */
.site-footer {
    background: #1D2129;
    border-top: none;
    padding: 40px 0 28px;
    font-size: 13px;
    color: #86909C;
}

.footer-nav {
    display: flex;
    justify-content: center;
    gap: 28px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.footer-nav a:hover {
    color: #C9CDD4;
}

.footer-legal {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin-bottom: 14px;
    flex-wrap: wrap;
}

.footer-legal a {
    display: inline-flex;
    align-items: center;
    gap: 4px;
}

.footer-meta {
    text-align: center;
    line-height: 1.8;
}

.footer-tip {
    margin-top: 6px;
    color: #6B7785;
    font-size: 12px;
}

/* --- 响应式 --- */
@media (max-width: 992px) {
    .price-grid {
        grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
    }
}

@media (max-width: 768px) {
    .container {
        padding: 0 16px;
    }

    .site-header {
        z-index: 201;
    }

    .header-inner {
        height: 56px;
    }

    .brand-block {
        flex: 1;
        min-width: 0;
    }

    .brand-block h1 {
        font-size: 16px;
        white-space: nowrap;
        overflow: hidden;
        text-overflow: ellipsis;
    }

    .menu-trigger {
        display: flex;
        flex-direction: column;
        justify-content: center;
        align-items: center;
        flex-shrink: 0;
        width: 40px;
        height: 40px;
        margin-left: 10px;
        border-radius: var(--radius-md);
        background: var(--bg-base);
        border: 1px solid var(--surface-border);
        cursor: pointer;
        gap: 5px;
        z-index: 202;
        -webkit-tap-highlight-color: transparent;
    }

    body.menu-open .menu-trigger {
        background: var(--brand-blue-soft);
        border-color: var(--brand-blue);
    }

    .menu-bar {
        display: block;
        width: 18px;
        height: 2px;
        background: var(--text-primary);
        border-radius: 1px;
        transition: transform 0.3s ease, opacity 0.2s ease;
    }

    body.menu-open .menu-bar:nth-child(1) {
        transform: translateY(7px) rotate(45deg);
    }

    body.menu-open .menu-bar:nth-child(2) {
        opacity: 0;
    }

    body.menu-open .menu-bar:nth-child(3) {
        transform: translateY(-7px) rotate(-45deg);
    }

    .menu-backdrop {
        display: block;
        position: fixed;
        inset: 0;
        background: rgba(0, 0, 0, 0.4);
        opacity: 0;
        visibility: hidden;
        pointer-events: none;
        z-index: 199;
        transition: opacity 0.3s ease, visibility 0.3s ease;
    }

    body.menu-open .menu-backdrop {
        opacity: 1;
        visibility: visible;
        pointer-events: auto;
    }

    .site-nav {
        position: fixed;
        top: 0;
        right: 0;
        width: min(280px, 80vw);
        height: 100dvh;
        height: 100vh;
        padding: 0;
        background: var(--surface);
        border-left: 1px solid var(--surface-border);
        box-shadow: -8px 0 32px rgba(0, 0, 0, 0.1);
        z-index: 200;
        transform: translateX(100%);
        transition: transform 0.35s cubic-bezier(0.4, 0, 0.2, 1);
        overflow-y: auto;
    }

    body.menu-open .site-nav {
        transform: translateX(0);
    }

    .nav-panel-head {
        display: flex;
        align-items: center;
        height: 56px;
        padding: 0 20px;
        border-bottom: 1px solid var(--surface-border);
    }

    .nav-panel-label {
        font-size: 13px;
        font-weight: 600;
        color: var(--text-tertiary);
        letter-spacing: 1px;
    }

    .nav-menu {
        flex-direction: column;
        gap: 2px;
        padding: 12px;
    }

    .nav-link a {
        display: flex;
        align-items: center;
        min-height: 48px;
        padding: 0 16px;
        font-size: 15px;
        border-radius: var(--radius-md);
    }

    .nav-link a:hover {
        background: var(--bg-base);
    }

    .nav-link.is-current a {
        background: var(--brand-blue-soft);
        color: var(--brand-blue);
    }

    .nav-link.is-current a::after {
        display: none;
    }

    .page-main {
        padding: 20px 0 40px;
    }

    .order-panel {
        padding: 24px 18px;
        margin-bottom: 20px;
    }

    .block-heading {
        font-size: 18px;
        margin-bottom: 18px;
    }

    .field-row {
        margin-bottom: 22px;
    }

    .field-input-wrap {
        max-width: 100%;
    }

    .price-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 10px;
    }

    .price-card {
        padding: 14px 10px;
    }

    .price-coins {
        font-size: 18px;
    }

    .channel-list {
        flex-direction: column;
    }

    .channel-item {
        width: 100%;
        justify-content: center;
    }

    .order-footer {
        flex-direction: column;
        align-items: stretch;
        text-align: center;
    }

    .summary-amount {
        font-size: 22px;
        display: block;
        margin-left: 0;
        margin-top: 4px;
    }

    .btn-primary {
        width: 100%;
    }

    .content-columns {
        grid-template-columns: 1fr;
        gap: 16px;
    }

    .content-card {
        padding: 22px 18px;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 12px;
    }

    .brand-logo {
        width: 30px;
        height: 30px;
    }

    .brand-block h1 {
        font-size: 15px;
    }

    .order-panel {
        padding: 18px 14px;
    }

    .block-heading {
        font-size: 16px;
        padding-left: 10px;
    }

    .field-text {
        height: 44px;
        font-size: 14px;
    }

    .price-coins {
        font-size: 16px;
    }

    .price-coins::after {
        font-size: 11px;
    }

    .price-rmb {
        font-size: 11px;
    }

    .qa-body {
        font-size: 12px;
        padding-left: 0;
        margin-top: 4px;
    }

    .footer-nav {
        gap: 12px;
        font-size: 12px;
    }

    .footer-legal {
        flex-direction: column;
        align-items: center;
        font-size: 11px;
    }

    .footer-meta {
        font-size: 11px;
        padding: 0 8px;
    }
}